This invention relates to a semiconductor substrate having a single crystalline silicon semiconductor layer formed on an insulator layer, such as a silicon on insulator (SOI) substrate or a silicon on sapphire (SOS) substrate, and a method for producing the semiconductor substrate. More specifically, the invention relates to a semiconductor substrate having a silicon layer with minimal dislocation or few defects and with satisfactory surface flatness, and a method for producing the semiconductor substrate. The invention also concerns a semiconductor device formed on the semiconductor substrate, and a method for producing the semiconductor device.
SOI and SOS have been known as substrate materials having a structure in which a single crystalline silicon semiconductor layer is formed on an insulator. In the present specification, semiconductor substrates (including the SOI substrate and the SOS substrate) having a single crystalline silicon semiconductor layer formed on an insulator layer are collectively called SOI substrates. These SOI substrates are applied widely to the preparation of devices, and surpass ordinary silicon substrates in the following respects:
(1) Excellency in high speed characteristics because of decreased parasitic capacitance
(2) High resistance to soft error
(3) Latch up free
(4) Omissibility of the well forming process.
To realize these advantages in device performance, the following methods for producing the SOI substrates have been available:
(i) Bonding method: A silicon single crystalline substrate is bonded to another silicon single crystalline substrate, whose surface has been thermally oxidized, by heat treatment or with the use of an adhesive, and then one of the silicon layers is converted to a uniform thin film by mechanical polishing or chemical etching.
(ii) SIMOX (separation by ion implanted oxide) method: Oxygen ions are implanted into a silicon substrate, and then this substrate is heat treated to prepare a buried SiO2 (silicon oxide) layer in the silicon substrate.
(iii) Solid phase epitaxial growth method: The surface of a silicon substrate is oxidized, whereafter a window is opened in a part of the resulting oxide film to expose the silicon substrate, on which an amorphous silicon layer is grown. Then, heat treatment is applied to crystallize the amorphous silicon layer by lateral solid phase epitaxial growth, starting at the portion in contact with the exposed silicon.
(iv) Heteroepitaxial growth method: A single crystalline silicon layer is grown on an insulating oxide substrate, or the oxide or fluoride layer which is deposited on a silicon substrate by CVD or the like.
However, these methods have both merits and demerits, and still remain problematical in productivity and quality. With the bonding method, for example, the silicon substrate itself needs to be formed into a thin film, but it is extremely difficult to etch or polish the silicon substrate accurately and uniformly to a thickness of 1 xcexcm or less. The SIMOX method has been studied for a long time, but has posed problems about productivity and cost, because a large amount of oxygen ions must be implanted into the silicon substrate in order to form the buried oxide film of SiO2 in the silicon substrate. This method also involves the problems of many crystalline defects present in the silicon layer, and the presence of defects, called pipes, in the buried oxide film.
In addition, the bonded SOI substrate and the SIMOX substrate have the drawbacks that the drain breakdown voltage and the ESD (electrostatic discharge) of a device prepared thereon (e.g., a field effect transistor) are low. These are problems about quality. The drain breakdown voltage refers to a phenomenon encountered with the device being an FET (field effect transistor), the phenomenon that when the device acts as an FET, hot carriers occurring in the junction between the body and the drain accumulate in the body, abruptly increasing a drain current flowing among the drain, the body and the source, and lowering the breakdown voltage. The ESD refers to breakdown voltage at which the device is broken by an electric shock such as static electricity. According to the specifications, the value of this parameter is 2,000 V, at which devices can usually withstand the static electricity generated by a human.
As one of the SOI technique, the SOS technology is known. The SOS substrate has been used mainly for devices requiring radiation hardness in addition to the features of the SOI substrate, such as small parasitic capacitance. The SOS substrate has features that noise throughout this substrate is low, because of a thick insulating layer. With the SOS substrate, moreover, the life time of carriers at the interface between the silicon layer and sapphire is short. When the FET works, therefore, hot carriers occurring in the junction between the body and the drain immediately recombine, and minimally accumulate in the body. Hence, the current flowing among the drain, the body and the source does not increase rapidly, so that the breakdown voltage does not decrease. That is, high drain breakdown voltage is a remarkable feature of the SOS substrate. However, the SOS substrate is prepared by heteroepitaxial growth of silicon on a sapphire substrate. Differences in lattice constant and thermal expansion coefficient between the silicon layer and the sapphire substrate (xcex1-Al2O3) lead to many crystalline defects and great surface roughness, which are remaining as problems.
As an SOI substrate having an intermediate layer, such as an oxide layer or a fluoride layer, on a silicon substrate, and a single crystalline silicon layer epitaxially grown on the intermediate layer, the one having an intermediate layer of, that is, xcex3-Al2O3 is known (Japanese Patent Application Laid-open No. 1-261300 (1989)). With such an SOI substrate, it is similarly expected that the life time of carriers at the interface between the silicon layer and the intermediate layer will be short, and thus high drain breakdown voltage comparable to that of the SOS substrate will be obtained. This type of substrate also has the problems of poor crystallinity and large surface roughness of the silicon layer due to differences in lattice constant and thermal expansion coefficient.
A method known to improve the crystallinity of the silicon layer in the SOS substrate involves implanting silicon ions into the silicon layer to make the interface with the sapphire amorphous, and then annealing the layer to recrystallize it (U.S. Pat. No. 4,177,084). According to this method, the silicon layer has fewer crystalline defects and higher crystallinity than that heteroepitaxially grown on a sapphire substrate, but still has about 109 crystalline defects, especially stacking faults, per cm2 remaining therein.
The silicon layer in these SOS substrates and SOI substrates also has the problem that the density of crystalline defects is higher at a site closer to the interface with the insulating substrates or the insulating layer on silicon substrate. This means that very many crystalline defects are contained in a thin silicon layer with a thickness of 0.05 to 0.3 xcexcm, as in the case of preparation of a high speed, low electric power consumption device.
The silicon layer in these SOS substrates and SOI substrates, moreover, is poor in orientation, and may include components of a (110)-plane or a (111)-plane in a (001)-plane. In addition, the silicon layer in these SOS substrates and SOI substrates include distortion, because of a large difference between the lattice constant of the (001)-plane grown parallel to the substrate surface and the lattice constant of a (100)-plane grown perpendicular to the substrate surface.
Compared with the bonded SOI substrate or the SIMOX substrate, the SOS substrate or the SOI substrate with an intermediate layer, such as an oxide layer or fluoride layer, deposited on a silicon substrate is poor in the crystallinity and surface flatness of the silicon layer. If a semiconductor device, such as MOSFET (metal-oxide-semiconductor field effect transistor), is formed on any of these substrates, flicker noise may be caused, or the operating performance or reliability of the FET may be deteriorated due to a decrease in breakdown voltage, ESD, effective mobility or transconductance.
As a method for improving the surface flatness of the silicon layer, it is known to heat-treat a bonded SOI substrate, having an insulator layer of SiO2, in a deoxidizing atmosphere (see Japanese Patent Application Laid-open No. 5-217821 (1993)). This method improved flatness, but showed no improvement in drain breakdown voltage or ESD, because the underlying layer is SiO2.
To ensure reliability of the device, it is preferred for the drain breakdown voltage or ESD to be higher. In an SOS substrate, or an SOI substrate having an intermediate layer, such as an oxide layer or fluoride layer, deposited on a silicon substrate, and a crystalline silicon layer epitaxially grown on the intermediate layer, it will be extremely useful for the performance and reliability of the device if the crystallinity and surface flatness of the silicon layer are improved, whereby the device performance ascribed to these properties is upgraded, or if the drain breakdown voltage or ESD is further increased.
The present invention aims to solve the problems with the conventional SOS substrate, or the conventional SOI substrate having an intermediate layer, such as an oxide layer or fluoride layer, deposited on a silicon substrate, and a silicon layer epitaxially grown on the intermediate layer; to provide an SOI substrate satisfactory in crystallinity and surface flatness, and having a crystalline defect density uniformly low in the depth direction; and to provide a semiconductor device having excellent properties, such as high speed, low flicker noise, high drain breakdown voltage, and high ESD, the semiconductor device being formed on the SOI substrate.
Under these circumstances, the inventors of the present invention found the following facts when producing an SOS substrate by growing a silicon layer on a sapphire substrate, or when producing an SOI substrate by depositing an oxide layer or a fluoride layer, as an intermediate layer, on a silicon substrate, and growing a silicon layer on the deposited layer: (A) After growth of the silicon layer, heat treatment is performed in an oxidizing atmosphere to oxidize a part of the silicon layer on its surface side. The resulting silicon oxide layer is etched with hydrofluoric acid, whereby a highly oriented silicon layer with few defects is left behind. (B) This silicon layer is used as a seed layer, and a silicon layer is regrown homoepitaxially on the seed layer, whereby a highly crystalline, highly oriented silicon layer with very few defects can be formed. These findings led the inventors to accomplish the present invention.
The inventors also found the following facts when producing an SOS substrate by growing a silicon layer on a sapphire substrate, or when producing an SOI substrate by depositing an oxide layer or a fluoride layer, as an intermediate layer, on a silicon substrate, and growing a silicon layer on the deposited layer: (C) After growth of the silicon layer, the silicon layer is heated in a hydrogen atmosphere, whereby the crystallinity and surface flatness of the silicon layer are markedly improved. (D) While the silicon layer is being grown, its growth is interrupted, and the system is heat treated in a hydrogen atmosphere to improve the surface flatness and crystallinity of the silicon layer. Then, epitaxial growth of the silicon layer is performed again. As a result, there can be prepared a silicon layer very satisfactory in surface flatness and minimal in dislocation or defects due to the lattice mismatch, that is a problem with heteroepitaxial growth. These findings led the inventors to accomplish the present invention.
The inventors further found the following fact when MOSFET, for example, is formed on an SOI substrate prepared by the above described manufacturing method, the SOI substrate having few defects, having high crystallinity and high orientation, and minimal in surface roughness, its performance can be remarkably improved, such as increases in operating speed and ESD, and a decrease in flicker noise, in comparison with conventional products. This finding led the inventors to accomplish the present invention.
That is, an SOI substrate claimed in claim 1 of the present invention is an SOI substrate comprising an insulating layer on silicon substrate, and a crystalline silicon layer epitaxially grown on the insulating layer on silicon substrate, the insulating layer on silicon substrate being composed of a single crystalline oxide substrate, or a multiple-layer substrate comprising a silicon substrate and a crystalline oxide layer or fluoride layer deposited on the silicon substrate, wherein the defect density of the crystalline silicon layer is not more than 4xc3x97108/cm2, and the surface roughness of the crystalline silicon layer is not more than 4 nm but not less than 0.05 nm.
An SOI substrate claimed in claim 2 of the present invention is the SOI substrate of claim 1, wherein the defect density of the crystalline silicon layer is not more than 4xc3x97108/cm2 in an entire depth direction.
An SOI substrate claimed in claim 3 of the present invention is the SOI substrate of claim 1, wherein the defect density of the crystalline silicon layer is not more than 1xc3x97107/cm2.
An SOI substrate claimed in claim 4 of the present invention is the SOI substrate of claim 1, wherein the defect density of the crystalline silicon layer is not more than 1xc3x97107/cm2 in an entire depth direction.
An SOI substrate claimed in claim 5 of the present invention is the SOI substrate of claim 1, wherein the full width at half maximum of the X-ray diffraction rocking curve of a (004)-peak in the crystalline silicon layer, grown parallel to the surface of the substrate, is not more than 1,000 arcsec but not less than 100 arcsec.
An SOI substrate claimed in claim 6 of the present invention is the SOI substrate of claim 1, wherein the lattice constant of a silicon (100)-plane in the crystalline silicon layer perpendicular to the surface of the substrate is not less than 5.41 angstroms but not more than 5.44 angstroms.
An SOI substrate claimed in claim 7 of the present invention is the SOI substrate of claim 1, wherein the lattice constant of a silicon (001)-plane in the crystalline silicon layer parallel to the surface of the substrate is not more than 5.44 angstroms but not less than 5.41 angstroms.
An SOI substrate claimed in claim 8 of the present invention is the SOI substrate of claim 1, wherein the ratio of the lattice constant of a silicon (001)-plane in the crystalline silicon layer parallel to the surface of the substrate to the lattice constant of a silicon (100)-plane in the crystalline silicon layer perpendicular to the surface of the substrate is not more than 1.005 but not less than 0.995.
An SOI substrate claimed in claim 9 of the present invention is the SOI substrate of claim 1, wherein the ratio of the intensity of a 220-reflection to the intensity of a 004-reflection in the crystalline silicon layer parallel to the surface of the substrate, both reflections determined in X-ray diffraction measurement, is not more than 0.1.
An SOI substrate claimed in claim 10 of the present invention is the SOI substrate of claim 1, wherein the insulating layer on silicon substrate is the single crystalline oxide substrate, and the single crystalline oxide substrate is a sapphire substrate.
An SOI substrate claimed in claim 11 of the present invention is the SOI substrate of claim 1, wherein the insulating layer on silicon substrate is the multiple-layer substrate, and the crystalline oxide layer deposited on the silicon substrate as a substrate of the multiple-layer substrate comprises any of xcex1-Al2O3, xcex3-Al2O3, xcex8-Al2O3, MgO.Al2O3, CeO2, SrTiO3, (Zr1xe2x88x92x,Yx)Oy, Pb(Zr,Ti)O3, LiTaO3, and LiNbO3, and the fluoride layer comprises CaF2.
A method for producing an SOI substrate claimed in claim 12 of the present invention is a method for producing an SOI substrate having a silicon layer with a low defect density formed on an insulating layer on silicon substrate, comprising the steps of:
(a) forming a silicon layer on the insulating layer on silicon substrate;
(b) heat treating the silicon layer in an oxidizing atmosphere to oxidize a part of a surface side of the silicon layer; and
(c) removing a silicon oxide film formed in the preceding step (b) by etching.
A method for producing an SOI substrate claimed in claim 13 of the present invention is a method for producing an SOI substrate having a silicon layer with a low defect density formed on an insulating layer on silicon substrate, comprising the steps of:
(a) forming a first silicon layer on the insulating layer on silicon substrate;
(b) heat treating the first silicon layer in an oxidizing atmosphere to oxidize a part of a surface side of the first silicon layer;
(c) removing a silicon oxide film formed in the preceding step (b) by etching; and
(d) epitaxially growing a second silicon layer on the remaining first silicon layer.
A method for producing an SOI substrate claimed in claim 14 of the present invention is the method of claim 13, further comprising repeating the steps (b) to (d) two or more times on condition that a silicon layer formed in the step (d) is regarded as the first silicon layer formed in the step (a).
A method for producing an SOI substrate claimed in claim 15 of the present invention is the method of any one of claims 12 to 14, wherein the oxidizing atmosphere contains a gas mixture of oxygen and hydrogen, or contains steam.
A method for producing an SOI substrate claimed in claim 16 of the present invention is the method of any one of claims 12 to 14, wherein the temperature of heat treatment in the oxidizing atmosphere is not lower than 600xc2x0 C. but not higher than 1,300xc2x0 C.
A method for producing an SOI substrate claimed in claim 17 of the present invention is the method of any one of claims 12 to 14, wherein the temperature of heat treatment in the oxidizing atmosphere is not lower than 800xc2x0 C. but not higher than 1,200xc2x0 C.
A method for producing an SOI substrate claimed in claim 18 of the present invention is the method of claim 13 or 14, wherein the temperature for epitaxial growth of the second silicon layer on the remaining first silicon layer is not lower than 550xc2x0 C. but not higher than 1,050xc2x0 C.
A method for producing an SOI substrate claimed in claim 19 of the present invention is the method of claim 13 or 14, wherein the temperature for epitaxial growth of the second silicon layer on the remaining first silicon layer is not lower than 650xc2x0 C. but not higher than 950xc2x0 C.
A method for producing an SOI substrate claimed in claim 20 of the present invention is the method of claim 13 or 14, wherein the remaining first silicon layer is heat treated in a hydrogen atmosphere or in a vacuum before the step of epitaxially growing the second silicon layer on the remaining first silicon layer.
A method for producing an SOI substrate claimed in claim 21 of the present invention is the method of claim 13 or 14, wherein no silicon oxide is formed on the surface of the remaining first silicon layer or in the second silicon layer in the step of epitaxially growing the second silicon layer on the remaining first silicon layer.
A method for producing an SOI substrate claimed in claim 22 of the present invention is the method of claim 13 or 14, wherein the base pressure of a growth chamber in an apparatus used in epitaxially growing the second silicon layer on the remaining first silicon layer is set at 10xe2x88x927 Torr or less.
A method for producing an SOI substrate claimed in claim 23 of the present invention is the method of claim 13 or 14, wherein a method for epitaxially growing the second silicon layer on the remaining first silicon layer is UHV-CVD or MBE.
A method for producing an SOI substrate claimed in claim 24 of the present invention is the method of claim 13 or 14, wherein when epitaxially growing the second silicon layer on the remaining first silicon layer, a growth temperature is set to be high only at an initial stage of growth.
A method for producing an SOI substrate claimed in claim 25 of the present invention is the method of claim 24, wherein a method for epitaxially growing the second silicon layer is APCVD or LPCVD.
A method for producing an SOI substrate claimed in claim 26 of the present invention is the method of claim 12, further including the step of heat treating the SOI substrate in a nitrogen atmosphere after the step of removing the silicon oxide film by etching.
A method for producing an SOI substrate claimed in claim 27 of the present invention is the method of claim 13 or 14, further including the step of heat treating the SOI substrate in a nitrogen atmosphere after the step of epitaxially growing the second silicon layer.
A method for producing an SOI substrate claimed in claim 28 of the present invention is the method of claim 26 or 27, further including the step of heat treating the SOI substrate in an oxidizing atmosphere after the step of heat treating the SOI substrate in the nitrogen atmosphere.
A method for producing an SOI substrate claimed in claim 29 of the present invention is the method of claim 12, further including the step of heat treating the SOI substrate in a hydrogen atmosphere after the step of removing the silicon oxide film by etching.
A method for producing an SOI substrate claimed in claim 30 of the present invention is the method of claim 13 or 14, further including the step of heat treating the SOI substrate in a hydrogen atmosphere after the step of epitaxially growing the second silicon layer.
A method for producing an SOI substrate claimed in claim 31 of the present invention is the method of claim 29 or 30, wherein the temperature of the heat treatment in a hydrogen atmosphere is not lower than 800xc2x0 C. but not higher than 1,200xc2x0 C.
A method for producing an SOI substrate claimed in claim 32 of the present invention is the method of any one of claims 12 to 31, further including the step of implanting silicon ions after the step of forming the first silicon layer, to make a deep portion of the silicon layer amorphous, and performing annealing for recrystallization.
A method for producing an SOI substrate claimed in claim 33 of the present invention is the method of claim 32, wherein the annealing is performed first in a nitrogen atmosphere, and then performed in an oxidizing atmosphere.
A method for producing an SOI substrate claimed in claim 34 of the present invention is the method of claim 33, further including the step of removing a silicon oxide film by etching after the annealing in the oxidizing atmosphere.
A method for producing an SOI substrate claimed in claim 35 of the present invention is the method of claim 12, further comprising the step of applying chemical and/or mechanical polishing to the silicon layer after the step of removing the silicon oxide film by etching.
A method for producing an SOI substrate claimed in claim 36 of the present invention is the method of claim 13 or 14, further comprising the step of applying chemical and/or mechanical polishing to the silicon layer after the step of epitaxially growing the second silicon layer.
A method for producing an SOI substrate claimed in claim 37 of the present invention is the method of any one of claims 12 to 36, wherein the step of forming the first silicon layer on the insulating layer on silicon substrate is the step of epitaxially growing the first silicon layer on the insulating layer on silicon substrate.
A method for producing an SOI substrate claimed in claim 38 of the present invention is the method of any one of claims 12 to 37, wherein the insulating layer on silicon substrate is a single crystalline oxide substrate.
A method for producing an SOI substrate claimed in claim 39 of the present invention is the method of claim 38, wherein the insulating layer on silicon substrate is a sapphire substrate.
A method for producing an SOI substrate claimed in claim 40 of the present invention is the method of any one of claims 12 to 37, wherein the insulating layer on silicon substrate is a multiple-layer substrate comprising a silicon substrate as a substrate and a crystalline oxide layer or fluoride layer deposited on the silicon substrate.
A method for producing an SOI substrate claimed in claim 41 of the present invention is the method of claim 40, wherein the crystalline oxide layer comprises any of xcex1-Al2O3, xcex3-Al2O3, xcex8-Al2O3, MgO.Al2O3, CeO2, SrTiO3, (Zr1xe2x88x92x,Yx)Oy, Pb(Zr,Ti)O3, LiTaO3, and LiNbO3, and the crystalline fluoride layer comprises CaF2.
A method for producing an SOI substrate claimed in claim 42 of the present invention is a method for producing an SOI substrate having a silicon layer with a low defect density formed on an insulating layer on silicon substrate, comprising the step of:
heat treating the silicon layer in a hydrogen atmosphere after forming the silicon layer on the insulating layer on silicon substrate.
A method for producing an SOI substrate claimed in claim 43 of the present invention is a method for producing an SOI substrate having a silicon layer with a low defect density formed on an insulating layer on silicon substrate, comprising the steps of:
(a) forming a first silicon layer on the insulating layer on silicon substrate;
(b) heat treating the first silicon layer in a hydrogen atmosphere; and
(c) epitaxially growing a second silicon layer on the first silicon layer heat treated in a hydrogen atmosphere.
A method for producing an SOI substrate claimed in claim 44 of the present invention is the method of claim 43, wherein the steps (a) to (c) are performed in situ.
A method for producing an SOI substrate claimed in claim 45 of the present invention is the method of any one of claims 42 to 44, wherein the temperature of the heat treatment in a hydrogen atmosphere is not lower than 800xc2x0 C. but not higher than 1,200xc2x0 C.
A method for producing an SOI substrate claimed in claim 46 of the present invention is the method of any one of claims 42 to 45, further including the step of implanting silicon ions after the step of forming the first silicon layer, to make a deep portion of the silicon layer amorphous, and performing annealing for recrystallization.
A method for producing an SOI substrate claimed in claim 47 of the present invention is the method of claim 42 or 43, further including the step of implanting silicon ions after the step of heat treating the first silicon layer in a hydrogen atmosphere, to make a deep portion of the silicon layer amorphous, and performing annealing for recrystallization.
A method for producing an SOI substrate claimed in claim 48 of the present invention is the method of claim 46 or 47, wherein the annealing is performed first in a nitrogen atmosphere, and then performed in an oxidizing atmosphere.
A method for producing an SOI substrate claimed in claim 49 of the present invention is the method of claim 48, further including the step of removing a silicon oxide film by etching after the annealing in the oxidizing atmosphere.
A method for producing an SOI substrate claimed in claim 50 of the present invention is the method of claim 42, further comprising the step of applying chemical and/or mechanical polishing to the silicon layer after the step of heat treating the silicon layer in a hydrogen atmosphere.
A method for producing an SOI substrate claimed in claim 51 of the present invention is the method of claim 43, further comprising the step of applying chemical and/or mechanical polishing to the silicon layer after the step of epitaxially growing the second silicon layer.
A method for producing an SOI substrate claimed in claim 52 of the present invention is the method of any one of claims 42 to 51, wherein the step of forming the first silicon layer on the insulating layer on silicon substrate is the step of epitaxially growing the first silicon layer on the insulating layer on silicon substrate.
A method for producing an SOI substrate claimed in claim 53 of the present invention is the method of any one of claims 42 to 51, wherein the insulating layer on silicon substrate is a single crystalline oxide substrate.
A method for producing an SOI substrate claimed in claim 54 of the present invention is the method of claim 53, wherein the single crystalline oxide substrate is a sapphire substrate.
A method for producing an SOI substrate claimed in claim 55 of the present invention is the method of any one of claims 42 to 51, wherein the insulating layer on silicon substrate is a multiple-layer substrate comprising a silicon substrate as a substrate and a crystalline oxide layer or fluoride layer deposited on the silicon substrate.
A method for producing an SOI substrate claimed in claim 56 of the present invention is the method of claim 55, wherein the crystalline oxide layer comprises any of xcex1-Al2O3, xcex3-Al2O3, xcex8-Al2O3, MgO.Al2O3, CeO2, SrTiO3, (Zr1xe2x88x92x,Yx)Oy, Pb(Zr,Ti)O3, LiTaO3, and LiNbO3, and the crystalline fluoride layer comprises CaF2.
An SOI substrate claimed in claim 57 of the present invention is produced by the method of any one of claims 12 to 41.
An SOI substrate claimed in claim 58 of the present invention is produced by the method of any one of claims 42 to 56.
A semiconductor device claimed in claim 59 of the present invention is a semiconductor device having an SOI substrate used as a substrate, wherein the SOI substrate of any one of claims 1 to 11 is used as the SOI substrate, whereby device performance is improved.
A semiconductor device claimed in claim 60 of the present invention is the semiconductor device of claim 59, which is at least one of a field effect transistor and a bipolar transistor, and wherein the device performance improved by using the SOI substrate of any one of claims 1 to 11 as the SOI substrate of the semiconductor device are at least one of transconductance, cut-off frequency, flicker noise, and electrostatic discharge.
A semiconductor device claimed in claim 61 of the present invention is the semiconductor device of claim 59, which is MOSFET, and wherein the device performance improved by using the SOI substrate of any one of claims 1 to 11 as the SOI substrate of the semiconductor device are at least one of transconductance, cut-off frequency, flicker noise, electrostatic discharge, drain breakdown voltage, and dielectric breakdown charge density.
A semiconductor device claimed in claim 62 of the present invention is the semiconductor device of claim 59, which is a bipolar transistor, and wherein the device performance improved by using the SOI substrate of any one of claims 1 to 11 as the SOI substrate of the semiconductor device are at least one of transconductance, cut-off frequency, collector current, leakage current characteristics, and current gain.
A semiconductor device claimed in claim 63 of the present invention is the semiconductor device of claim 59, which is a diode, and wherein the device performance improved by using the SOI substrate of any one of claims 1 to 11 as the SOI substrate of the semiconductor device are at least one of reverse leakage current characteristics, forward bias current, and ideality factor.
A semiconductor device claimed in claim 64 of the present invention is the semiconductor device of claim 59, which is a semiconductor integrated circuit, and wherein the device performance improved by using the SOI substrate of any one of claims 1 to 11 as the SOI substrate of the semiconductor device are at least one of frequency characteristic, noise characteristic, amplification characteristic, and dissipation power characteristic.
A semiconductor device claimed in claim 65 of the present invention is the semiconductor device of claim 59, which is a semiconductor integrated circuit composed of MOSFET, and wherein the device performance improved by using the SOI substrate of any one of claims 1 to 11 as the SOI substrate of the semiconductor device are at least one of frequency characteristic, noise characteristic, amplification characteristic, and dissipation power characteristic.
A semiconductor device claimed in claim 66 of the present invention is a semiconductor device having an SOI substrate used as a substrate, wherein an SOI substrate produced by the method of any one of claims 12 to 41 is used as the SOI substrate, whereby device performance is improved.
A semiconductor device claimed in claim 67 of the present invention is a semiconductor device having an SOI substrate used as a substrate, wherein an SOI substrate produced by the method of any one of claims 42 to 56 is used as the SOI substrate, whereby device performance is improved.
A semiconductor device claimed in claim 68 of the present invention is the semiconductor device of claim 66 or 67, which is at least one of a field effect transistor and a bipolar transistor, and wherein the device performance is at least one of transconductance, cut-off frequency, flicker noise, and electrostatic discharge.
A semiconductor device claimed in claim 69 of the present invention is the semiconductor device of claim 66 or 67, which is MOSFET, and wherein the device performance is at least one of transconductance, cut-off frequency, flicker noise, electrostatic discharge, drain breakdown voltage, and dielectric breakdown charge density.
A semiconductor device claimed in claim 70 of the present invention is the semiconductor device of claim 66 or 67, which is a bipolar transistor, and wherein the device performance is at least one of transconductance, cut-off frequency, collector current, leakage current characteristics, and current gain.
A semiconductor device claimed in claim 71 of the present invention is the semiconductor device of claim 66 or 67, which is a diode, and wherein the device performance is at least one of reverse leakage current characteristic, forward bias current, and ideality factor.
A semiconductor device claimed in claim 72 of the present invention is the semiconductor device of claim 66 or 67, which is a semiconductor integrated circuit, and wherein the device performance is at least one of frequency characteristic, noise characteristic, amplification characteristic, and dissipation power characteristic.
A semiconductor device claimed in claim 73 of the present invention is the semiconductor device of claim 66 or 67, which is a semiconductor integrated circuit composed of MOSFET, and wherein the device performance is at least one of frequency characteristic, noise characteristic, amplification characteristic, and dissipation power characteristic.
A method for producing a semiconductor device claimed in claim 74 of the present invention is a method for producing a semiconductor device on an SOI substrate comprising an insulating layer on silicon substrate, and a silicon layer formed on the insulating layer on silicon substrate, comprising the steps of:
(a) forming a first silicon layer on the insulating layer on silicon substrate;
(b) heat treating the first silicon layer in an oxidizing atmosphere to oxidize a part of a surface side of the first silicon layer;
(c) removing a silicon oxide film formed in the preceding step (b) by etching;
(d) epitaxially growing a second silicon layer on the remaining first silicon layer; and
(e) heat treating a silicon layer, formed in the preceding step (d), in an oxidizing atmosphere to oxidize a part of a surface side of the silicon layer, and then removing a silicon oxide film, which has been formed, by etching to adjust the silicon layer to a desired thickness.
A method for producing a semiconductor device claimed in claim 75 of the present invention is the method of claim 74, further including the step of implanting silicon ions after the step of forming the first silicon layer, to make a deep portion of the silicon layer amorphous, and performing annealing for recrystallization.
A method for producing a semiconductor device claimed in claim 76 of the present invention is the method of claim 74, further comprising the step of heat treating a silicon layer in a hydrogen atmosphere after the step (d) of epitaxially growing the second silicon layer.
A method for producing a semiconductor device claimed in claim 77 of the present invention is the method of claim 74, further comprising applying chemical and/or mechanical polishing to a silicon layer before or after the step (e).
A method for producing a semiconductor device claimed in claim 78 of the present invention is a method for producing a semiconductor device on an SOI substrate comprising an insulating layer on silicon substrate, and a silicon layer formed on the insulating layer on silicon substrate, including the steps of:
(a) forming a silicon layer on the insulating layer on silicon substrate;
(b) heat treating the silicon layer in a hydrogen atmosphere; and
(c) heat treating the silicon layer in an oxidizing atmosphere to oxidize a part of a surface side of the silicon layer, and then removing a silicon oxide film, which has been formed, by etching to adjust the silicon layer to a desired thickness.
A method for producing a semiconductor device claimed in claim 79 of the present invention is the method of claim 78, further including the step of implanting silicon ions after the step of forming the first silicon layer, to make a deep portion of the silicon layer amorphous, and performing annealing for recrystallization.
A method for producing a semiconductor device claimed in claim 80 of the present invention is the method of claim 78, further comprising performing chemical and/or mechanical polishing of the silicon layer before or after the step (c).
A method for producing a semiconductor device claimed in claim 81 of the present invention is a method for producing a semiconductor device on an SOI substrate comprising an insulating layer on silicon substrate, and a silicon layer formed on the insulating layer on silicon substrate, comprising the steps of:
(a) forming a first silicon layer on the insulating layer on silicon substrate;
(b) heat treating the first silicon layer in a hydrogen atmosphere;
(c) epitaxially growing a second silicon layer on the first silicon layer heat treated in a hydrogen atmosphere; and
(d) heat treating a silicon layer, formed in the step (c), in an oxidizing atmosphere to oxidize a part of a surface side of the silicon layer, and then removing a silicon oxide film, which has been formed, by etching to adjust the silicon layer to a desired thickness.
A method for producing a semiconductor device claimed in claim 82 of the present invention is the method of claim 81, further including the step of implanting silicon ions after the step of forming the first silicon layer, to make a deep portion of the silicon layer amorphous, and performing annealing for recrystallization.
A method for producing a semiconductor device claimed in claim 83 of the present invention is the method of claim 81, further comprising applying chemical and/or mechanical polishing to the resulting silicon layer before or after the step (d).